LIGHT EMITTING DIODE HAVING HETEROGENEOUS PROTRUSION STRUCTURES

• US 20140138613A1
• Filed: 11/16/2012
• Published: 05/22/2014
• Est. Priority Date: 11/16/2012
• Status: Active Grant

• Current Assignee: Korea Photonics Technology Institute
• Original Assignee: Sang-Mook Kim
• Inventors: Kim, Sang-Mook, Baek, Jong-Hyeob
• Granted Patent: US 9,000,414 B2
• Time in Patent Office: Days
• US Class Current: 257/13
• CPC Class Codes: H01L 33/005 Processes
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/24 of the light emitting region, e.g. non-planar junction

Abstract

An object of the present invention is to provide a light emitting diode having a heterogeneous material structure and a method of manufacturing thereof, in which efficiency of extracting light to outside is improved by forming depressions and prominences configured of heterogeneous materials different from each other before or in the middle of forming a semiconductor material on a substrate in order to improve the light extraction efficiency.

Claims

1. A light emitting diode, comprising:

a substrate;

an n-type semiconductor layer formed on the substrate;

an active layer formed on the n-type semiconductor layer;

a p-type semiconductor layer formed on the active layer;

a transparent electrode layer formed on the p-type semiconductor layer;

a first electrode layer formed on the transparent electrode layer;

a second electrode layer formed in an area where the n-type semiconductor layer is exposed by etching the transparent electrode layer, the p-type semiconductor layer and the active layer;

a protrusion formed on at least one of the substrate, the n-type semiconductor layer, and the p-type semiconductor layer; and

a mask material formed on the top of the protrusion, wherein

the mask material has a refractive index that is different from a refractive index of the protrusion.

2. The light emitting diode according to claim 1, wherein the substrate comprises a material selected from the group consisting of sapphire, silicon carbide, gallium arsenic (GaAs), gallium nitride (GaN), aluminum gallium nitride (AlGa_1-xN, 0≦

x≦

1), and silicon (Si).

3. The light emitting diode according to claim 1, wherein the protrusion comprises a material selected from the group consisting of chrome (Cr), silicon dioxide (SiO₂), silicon nitride (Si₃N₄), silicon oxynitride (SiON), hafnium oxide (HfO), silver (Ag), and aluminum (Al).

4. The light emitting diode according to claim 1, wherein a flat surface of the protrusion is formed in a shape of a circle, a triangle, a rectangle or a polygon or in a shape of a point of a vertex.

10. The light emitting diode according to claim 1, wherein the protrusion has a bottom width of 0.2 to 1 μ

m, a height of 0.1 to 1 μ

m, and a distance of 0.05 μ

m to 1 μ

m between protrusions.

5. A method of manufacturing a light emitting diode having a heterogeneous material structure, the method comprising the steps of:

patterning a protruded pattern so that a first etch mask material having a certain refractive index may remain on a top surface of a substrate;

forming an n-type semiconductor layer on the substrate;

forming an active layer on the n-type semiconductor layer;

forming a p-type semiconductor layer on the active layer;

forming a transparent electrode layer on the p-type semiconductor layer;

etching a predetermined area of the transparent electrode layer, the active layer and the p-type semiconductor layer;

forming a first electrode layer on the transparent electrode layer; and

forming a second electrode layer in the area where the n-type semiconductor layer is exposed by etching the transparent electrode layer, the active layer and the p-type semiconductor layer.

6. The method according to claim 5, further comprising the step of forming a buffer layer, after the step of patterning a protruded pattern so that a first etch mask material having a certain refractive index may remain on a top surface of a substrate.

7. The method according to claim 5, wherein the step of patterning a protruded pattern so that a first etch mask material having a certain refractive index may remain on a top surface of a substrate includes the step of:

depositing the first etch mask material on the substrate;

patterning on the substrate;

partially etching the first etch mask material so that the first etch mask material may remain on a top of the pattern formed by the patterning step;

etching the substrate; and

cleaning the etched substrate.

8. The method according to claim 7, wherein the step of etching the first etch mask material includes the steps of:

depositing a second etch mask material having a certain refractive index on the top surface of the substrate where the first etch mask material remains;

patterning on the substrate; and

partially etching the second etch mask material so that the second etch mask material may remain on the top of the pattern formed by the patterning step.

9. The method according to claim 8, wherein the first and second etch mask materials contain at least two or more materials selected among chrome (Cr), silicon dioxide (SiO2), silicon nitride (Si3N4), silicon oxynitride (SiON), hafnium oxide (HfO), silver (Ag) and aluminum (Al).